1. Field of the Invention
The present invention relates to a liquid storing container, a liquid ejection head cartridge (which will sometimes be referred to hereinafter as an ink jet head) equipped with the same container and a liquid ejection head (which will sometimes be referred to hereinafter as an ink jet cartridge), and an liquid ejection recording apparatus (which will sometimes be referred to hereinafter as a liquid jet recording apparatus) in which the same cartridge is mounted for recording, and more particularly to a liquid storing container having an internal structure improved for stabilizing a liquid supply property, a liquid ejection head cartridge carrying the same container and a liquid ejection head, and a liquid ejection recording apparatus incorporating the same cartridge for recording.
2. Description of the Related Art
In general, an ink tank (including a type of being integrated with a recording head and a type in which an ink tank is replaceable separately) serving as a liquid storing container for use in the field of liquid jet recording (which will equally be referred to hereinafter as an ink jet recording) has a construction to adjust the holding capability of an ink stored in the ink tank for achieving excellent ink supply to a recording head which ejects a liquid (a liquid to be used for recording; including a type containing a coloring component(s), and a type not containing a coloring component but which acts on a liquid containing a coloring component for upgrading the recording quality, which hereinafter will be referred to simply as an ink). This holding capability is called negative pressure, because it is for making the pressure in an ink ejecting section of a recording head negative with respect to the atmosphere (a member for production of such a negative pressure will equally be referred to hereinafter as a negative pressure producing member).
As one of the easiest ways of producing such a negative pressure, there has been known a means in which an ink absorber made from a porous material such as a urethane foam is provided in an ink tank to utilize a capillary capability the ink absorber.
In addition, there has been proposed an ink tank (which will be referred to hereinafter as a juxtaposed type ink tank) in which, for the purpose of enhancing the volume efficiency of the ink in the interior of the ink tank, a chamber for accommodating the ink absorber and a chamber for storing the liquid directly are juxtaposed so that they are made to partially communicate with each other.
FIG. 10A is a cross-sectional view schematically showing a construction of an ink tank in which, as mentioned above, a chamber for accommodating the ink absorber and a chamber for storing the liquid directly are juxtaposed so that they are made to partially communicate with each other. The interior of the ink tank 10 is partitioned by a partition wall 38, having a communicating hole 40, into two spaces. One space is hermetically sealed except the communicating hole 40 of the partition wall 38 serves a liquid storage chamber 36 for storing an ink directly, while the other acts as a negative pressure producing member storage chamber 34 for accommodating a negative pressure producing member 32. On a wall surface defining this negative pressure producing member storage chamber 34, there are formed an atmosphere communication section (atmosphere communicating opening) 12 for introducing the atmosphere into a container resulting from ink consumption, and a supply opening 14 having an ink leading member 39 for leading the ink from the tank to a recording head section (not shown). In FIG. 10A, the area in which the negative pressure producing member holds the ink is indicated by an oblique-line section. Additionally, the ink stored in the space is indicated by a mesh section.
In the foregoing construction, on consumption of the ink in the negative pressure producing member 32 by the recording head, air is introduced through the atmosphere communication opening 12 into the negative pressure producing member storage chamber 34 passing into the liquid storage chamber 36 through the communicating hole 40 of the partition wall 38. Instead, the ink is put from the liquid storage chamber 36 through the communicating hole 40 of the partition wall 38 into the negative pressure producing member 32 in the negative pressure producing member storage chamber 34 (this operation will be referred to hereinafter as an air-liquid replacement operation). Accordingly, if the recording head consumes the ink, the ink is drawn into the negative producing member 32 according to the consumption thereof so that the negative pressure producing member 32 retains a constant quantity of ink to maintain the negative pressure to the recording head approximately constant, thus stabilizing the ink supply to the recording head.
In addition, in the example shown in FIG. 10A, in the vicinity of the communicating section between the negative producing member storage chamber 34 and the ink storage chamber 36, an atmosphere introducing groove 51 is provided as a structure to promote the introduction of the atmosphere, while, in the vicinity of the atmosphere communicating section, a space (buffer chamber) 44, not accommodating a negative pressure producing member, is defined by ribs 42.
In the conventional art, in many cases, the urethane foam has commonly been employed as the aforesaid negative pressure producing member (which is equally referred to as an ink absorber) as mentioned above. However, the urethane foam requires further improvement in the service efficiency of ink; besides, not always exhibiting a suitable characteristic depending on the ink property.
For this reason, this applicant has proposed the use of a fiber made from an olefin-based resin having a thermal plasticity, which shows, as an ink absorber, a superior ink property throughout a wide range.
Meanwhile, in a juxtaposed type tank shown in FIG. 10A, the important factors in the stable supply of an ink are the structure of a communicating hole constituting a connecting section between a negative pressure producing member storage chamber and a liquid storage chamber and the structure on the periphery thereof.
That is, in the case of the juxtaposed type ink tank, the bottom line is the stable introduction of air from the atmosphere communicating section (atmosphere communicating opening) 12 through the atmosphere introducing groove 51 of the partition wall 38 into the liquid storage chamber in connection with the ink consumption. If air is introduced through places other than this air introduction route, an unnecessary air-liquid replacement, not related to the ink consumption, takes place, which can cause an excessive supply of to leak toward the exterior of the tank.
In the case of the use of the urethane foam as the negative pressure producing member, since the urethane foam per se has a structure showing a high elasticity, it comes satisfactorily into contact with the communicating hole and an inner wall surface constituting the periphery thereof in a state accommodated in the negative pressure producing member storage chamber, which hardly causes the aforesaid unexpected air-liquid replacement, thus not creating problems on the practical use.
However, a fiber member involving fibers and displaying more preferable characteristics relating to a characteristic to the ink and a service efficiency as compared with the urethane foam does not exhibit a high elasticity because of its property on the material unlike the urethane foam (particularly, although a fiber member whose felt-like fibers do not run remarkably to one direction shows a relatively high elasticity, a fiber member made to have directionality can depend upon the direction the fibers extend in). Accordingly, sometimes, it does not reach an excellent contacting condition with an inner wall surface of an tank in a state accommodated in the negative pressure producing member storage chamber. Although the prevention from such an event relies upon high-accuracy cutoff, difficulty can be encountered in achieving a desirable cutoff accuracy.
Especially, in the case of the juxtaposed type ink tank in which, as shown in FIG. 10A, the ink supply is made from a lower section of the ink tank and the ink tank and the head are placed in a separated condition, in order to secure the close contact of the ink leading member 39 located in the ink supplying section with a filter placed at the tip portion of a supply pipe set in the head, there is a need to push up the aforesaid ink leading member 39 by the supply pipe when the ink tank is set on a mounting holder attached onto the head. At this time, the bottom surface of the absorber is simultaneously lifted by the influence of the pushed up ink leading member 39.
In the case of the urethane foam, the material itself has a high elasticity so that its local deformation absorbs the pushed-up ink leading member 39; accordingly, variation does not occur in the locating construction of the urethane foam near the communicating hole.
However, the fiber absorber occasionally displays poor elasticity due to the fiber directionality constituting the characteristic of the material; whereupon, the fiber absorber is also pushed up by the pushed-up ink leading member 39 so that variation occurs in the locating construction of the fiber absorber between the ink supplying section and the vicinity of the communicating hole, which tends to establish a passage between the bottom surface of the fiber absorber storage chamber and the bottom surface of the fiber absorber.
In such a juxtaposed type ink tank, the liquid storage chamber except the communicating hole must be sealed hermetically. In addition, for accomplishing stable air-liquid replacement, it is preferable that the communicating hole is covered with the negative pressure producing member.
Nevertheless, in the case of a conventional ink tank of a juxtaposed type juxtaposing a negative pressure producing member storage chamber and a liquid storage chamber as shown in FIG. 10B or 10C, since the communicating hole for making a connection between the negative pressure producing member storage chamber and the liquid storage chamber is defined by an inner wall organizing the tank bottom surface or the tank side surface, in the case in which the negative pressure such as the aforesaid fiber absorber is accommodated therein, the close adhesion between the fiber absorber and the ink tank case inner wall becomes insufficient due to the aforesaid cause such as the tank connection so that a gap (which will equally be referred to hereinafter as a path, an air path or a ridge line path) develops between the fiber absorber and the ink tank case inner wall; hence, this gap communicates with the communicating hole and further communicates with the external atmosphere, which can incur an unnecessary and expected air-liquid replacement to give rise to an external leak of ink.
FIG. 10D shows one example of an ink tank in which the unnecessary air-liquid replacement has occurred. An air path 60 defines an ink path when once communicating with the liquid storage chamber, thus producing the ink passage toward the supplying section.
FIG. 10E illustrates a section of the ink tank, indicated by oblique lines, where the air path 60 tending to produce the unnecessary air-liquid replacement develops easily. As illustrated, a gap (ridge line path) tends to develop in a ridge line of a joint between the wall surfaces.
As described above, if a fiber absorber having a directionality is employed as the negative pressure producing member, the failure of the close adhesion to the tank inner wall surface or the ridge line tends to occur, and if forcible insertion takes place, buckling will occur in the fiber absorber to incur unexpected ink surplus or to provide, for example, unsatisfactory ink supply ability or insufficient negative pressure.
As described above, if an air path develops to cause ink leakage from an ink supply opening, desirable printing becomes difficult, the ink drops onto a print medium or the printer body is contaminated with the ink, and even there is a possibility of, for example, soiling hands or clothes of the user at the ink tank replacement.
Accordingly, it is an object of the present invention to provide a liquid storing container which is of a juxtaposed type capable of, even if a fiber member having directionality and used as an absorber moves in the interior of a tank at the mounting of the tank, preventing the communication of an air path with an ink chamber so as not to create the aforesaid problems of ink leakage, deterioration of the print quality and others, and further to provide a liquid ejection head cartridge in which the same container and a liquid ejection head are integrated with each other and a liquid ejection recording apparatus in which the same cartridge is mounted for recording.
For achieving this object, in accordance with this invention, there is provided a liquid storing container attachable and detachable to and from recording means, comprising a negative pressure producing member storage chamber made to accommodate a negative pressure producing member and equipped with a liquid supplying section and an atmosphere communicating section, a liquid storage chamber having a communicating hole for establishing a communication with the negative pressure producing member storage chamber and made to define a substantially hermetically sealed space for storing a liquid to be supplied to the negative pressure producing member, a partition wall for establishing a partition between the negative pressure producing member storage chamber and the liquid storage chamber and for defining the communicating hole, and a path made in the vicinity of the communicating hole on the negative pressure producing member storage chamber side for introducing the atmosphere from the negative pressure producing member storage chamber into the liquid storage chamber, wherein the negative pressure producing member is made with a fiber material having directionality and the communicating hole is in a non-contacting condition with a ridge line defined by crossing of the partition wall and an inner wall constituting the negative pressure producing member storage chamber.
With this construction, even if an air path develops between the negative pressure producing member and an inner wall constituting the negative pressure producing member storage chamber or a ridge line portion, it is possible to prevent the air path from communicating through the communicating hole with the liquid storage chamber.
Accordingly, it is possible to prevent unnecessary air-liquid replacement for preventing unnecessary ink leakage from the liquid storing container, and to reduce the necessity to improve the accuracy for avoiding the occurrence of an air path, that is, to improve the margin for facilitating the manufacturing of the liquid storing container. In addition, even if a situation such as drop of the liquid storing container arises, since the possibility of the communication of the air path with the communicating hole is reducible, thus providing a liquid storing container, a liquid ejection head cartridge and a liquid ejection recording apparatus which are capable of improving their reliability.